In recent years, an image forming apparatus configured to form an image with an erasable developer and an erasing apparatus were introduced according to the demand for resource saving. The erasing apparatus erases an image by applying heat and light to a recording medium on which the image is formed with the erasable developer and erasing the developer. Therefore, the recording medium after the image is erased can be reused.
In some case, a recording medium an which an image is once formed is stapled or affixed with a tag or the like. Such a recording medium clogs a recording medium conveying path and causes a jam or damages the apparatus.
As measures against such a problem, there is proposed a technique for providing a detecting device configured to detect double feed and stopping conveyance of a recording medium when the double feed is detected.
There is also proposed a technique for providing, halfway in the recording medium conveying path, a sensor configured to detect the thickness of a recording medium and discharging the recording medium to the outside of the apparatus via the normal recording medium conveying path when the recording medium has unexpected thickness.